The conventional methods of manufacturing metal bats generally belong to either of the following two categories as illustrated on the appended FIGS. 1 and 2: (A) forming a bat by putting together a body portion (a), a large end (b), and a grip portion (c) made of metallic material, for example aluminum, with some kind of adhesive, wherein said body portion is formed by a swaging process, the large end is sealed with a rubber or plastic plug, and the grip portion is often covered with a knobbed rubber for preventing slippage; (B) forming a bat by welding together three metal pieces, the body portion (a') formed by a swaging process, the large end (b') and the grip portion (c') formed by a swaging or drawing process. The metal bats as per (A) are not free from being broken into pieces by detachment of the attached portions while in use, and the body portion may be subjected to be struck away. The bats as per (B) are likewise non-integral in material, so that the bats are not only unreliable with regard to strength but are also liable to be of high cost in manufacturing because of the diversification of processes. In addition, the process by which the bats (B) are made is apt to invite unequality of wall thickness of the material and also inherent brittleness at the heat affected zones in the case of fabricated construction, which means the products are still problematical or insufficient in durability, and even dangerous in possibly hurting the players.